"Joisey" is the way some New Yorkers mispronounced New Jersey (both leaving out the "New" and pronouncing "Jersey" badly). People who moved to New Jersey from New York and who prided themselves in not having the extreme accent of some people in their old New York neighborhoods would sometimes ridicule and imitate the way these New Yorkers referred to New Jersey as "Joisey." These days, some people from other parts of the country, or at least not from New Jersey, mistakenly think that "Joisey" is the way New Jerseyans commonly refer to their state.

I told my old neighbor that I've missed him ever since I moved to New Jersey, but he kept saying that I had left the old neighborhood to go to "joisey" and that now I was a "joisey goil."

How us New Jersey people DONT say Jersey
We say Jurzee, see New Jersey accentNot even people in North Jersey say it that way
Not even my cousins from NY say it
We have 8 million residents, do you really think all of them say "Joisey"? If you do than your dumb as hell.

I bet 90% of you who make fun of us have never been to New Jersey, and I bet I could make fun of your state but I don't cause I'm not some ignorant fuck who makes up shit.
NO ONE SAYS JOISEY.

1920's Betty Boop, caricturish, outdated notion of how New Jerseyians talk. Mostly propagated by middle of the country bumkins who have never left their home town.

Midwesterner1: I used to think people from Joisey all have big or slicked hair, live in an ethnic neighborhood and drive around in a Camaro. And when they weren't screaming at their girlfriend to Shut the Fuck Up they're stealin' somebodies hubcaps.